Method of combatting bacteria or fungi on plants using amino acid higher alkyl esters

ABSTRACT

Amino acid higher alkyl esters, salts thereof and their N-lower alkyl derivatives are useful for controlling numerous plant diseases. They exhibit excellent protective effect rather than curative effect and have no phytotoxicity, extremely low mammalian toxicity and cause no risk of pollution toward soils.

United States Patent [191 Misato et al.

[ June 28, 1974 METHOD OF COMBATTING BACTERIA OR F UNGI ON PLANTS USING AMINO ACID HIGHER ALKYL ESTERS [75] Inventors: Tomomasa Misato, Tokyo; Keng Tang Huang, Wako; Yasuo Homma, Fukuoka-Machi; Ryonosuke Yoshida, Kamakura; Tadaomi Saito', Yokohama; Akira Shimizu, Kawasaki, all of Japan [73] Assignees: Rikagaku Kenkyusho,, Wako-shi,

Saitamia-ken, Japan; Ajinomoto Co.,

Ltd., Tokyo, Japan [58] Field of Search 424/311 [56] References Cited FOREIGN PATENTS OR APPLICATIONS 961,304 6/1964 Great Britain Primary Examiner--lerome D. Goldberg Assistant Examiner--Allen J. Robinson Attorney, Agent, or Firm-Sherman & Shalloway [5 7] ABSTRACT Amino acid higher alkyl esters, salts thereof and their N-lower alkyl derivatives are useful for controlling numerous plant diseases. They exhibit excellent protective effect rather than curative effect and have no phytotoxicity, extremely low mammalian toxicity and cause no risk of pollution toward soils.

1 Claim, No Drawings METHOD OF COMBA'ITING BACTERIA OR FUNGI ON PLANTS USING AMINO ACID HIGHER,

" ALKYL ESTERS The present invention relates to an agricultural and horticultural fungicidal and bactericidal agent and to a method for the use thereof, and more particularly the present invention relates to fungicidal and bactericidal compositions for agricultural and horticultural use in which amino acid higher alkyl esters having eight 22 carbon atoms in its alkyl ester portion, salts thereof or their N-lower alkyl derivatives are the active ingredients.

Compounds of heavy metals such as copper, mercury and arsenic, as well as organophosphorus and organic chlorine compounds have been practically used for the control of plant diseases, but each of these fungicides cannot be necessarily said to be satisfactory one, because of its pollution toward soils, its strong medicinal harm on plants, its residual toxicity in food crops, its high mammalian toxicity or its irritiation to skin and eyes of humans.

i As the result of having ardently studied compounds which do not possess any of the above faults as recognized in the fungicides hitherto used and which exhibit preventive effect against the fungal plant diseases, we have now found that amino acid higher alkyl esters, salts thereof and their N-lower alkyl derivatives exhibit excellent preventive effectagainst numerous plant dis eases such as rice blast and rice leaf blight which are the main diseases of rice plant, citrus melanose, cucumber anthracnose, cucumber phytophthora rot, cucumber powdery mildew, cucumber downy mildew, tomato leaf mold, tomato late blight, tomato leaf spot and others, and that they have no phytotoxicity and have extremely low mammalian toxicity and cause no risk of pollution toward soils. 7

Amino acid higher alkyl esters, salts thereof or their N-substituted lower alkyl ester derivatives which are the active ingredients of the fungicidal composition in the present invention may be easily prepared by the known method per se. For example, amino acid or N lower alkyl derivative thereof is mixed with higher alcohol under heating and dry hydrogen chloride gas is introduced into the mixture, whereby most of amino acid is dissolved and the corresponding amino acid ester hydrochloride is formed. On cooling, the solidified product is washed with ether or aromatic hydrocarbon such as benzene to remove unreacted higher alcohol. The crude amino acid ester hydrochloride obtained is re crystallized from water, methanol or ethyl acetate to obtain highly purified amino acid higher alkyl ester hydrochloride or N-lower alkyl derivative thereof (hereinafter, referred to as amino acid higher alkyl ester salt, inclusive of both products) in 70 percent yield. In

order to obtain other salts, the amino acid higher alkyl ester hydrochloride is dissolved in an equivalent amount of alkaline aqueous solution and extracted with benzene, and then a mineral acid (e.g. sulfuric acid) or organic salt (e.g. acetic acid, acidic amino acid, pyroglutamic acid, p-toluenesulfonic acid and the like) is added directly or in the form of solution dissolved in a suitable solvent to benzene-extracted layer, whereupon the corresponding salt is formed. The solubility of the amino acid higher alkyl ester salts obtained thus varies depending on the kind of salts andthe length of carbon chain of the ester radical, but in general these salts are soluble in water. Free amino acid higher alkyl esters may be obtained by neutralizing their salts e.g. the hydrochlorides with alkaline aqueous solution.

For the preparation of amino acid higher alkyl ester salts, various kinds of amino acids such as a-amino acid, ,B-amino acid and w-amino'acid may be employed. Examples of suitable amino acid include neutral amino acids such as glycine, phenylglycine, alanine, a-alanine, B-aminobutyric acid, valine, norvaline, leucine, isoleucine, norleucine, phenylalanine, 'p-nitrophenylalanine, tryptophane, proline and e-aminocapric acid; acidic amino acids such as glutamic acid, aminomaloic acid, a-aminoadipic acid, a-aminopimeric acid, cysteic acid and homocysteic acid; basic amino acids such as lysine, omithine, arginine and histidine. Other examples of the neutral, acidic, and basic amino acids are sulfurcontaining amino acids such as methionine, cysteine, cystine, homocystine, B-thiolleucine and ethionine; hydroxyamino acids such as threonine, serine, ,B-hydroxyleucine, homoserine, oxyproline, dopa, tyrosine, nitrotyrosine and B-hydroxyglutamic acid; in addition, diaminodicarboxylic acids such as a,a-diaminocitric acid, a,a'-diaminoglutaric acid and a,a-diaminoadipic acid; N-methyl or N-ethyl derivatives of these amino acids such as N,N'-dimethylalanine, N,N- dimethylphenylalanine and the like.

These amino acids may be optionally active L- or D- form or racemic form. As higher alcohols for esteriflcation, natural or syntheticaliphatic alcohols having eight to 22 carbon atoms are employed, but lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol and the like are especially preferred. The amino acid alkyl ester salts wherein alkyl groups have less than seven carbon atoms have weak fungicidal activity while amino acid alkyl ester salts wherein alkyl groups have more than 23 carbon atoms have very little water solubility owing to their long hydrophobic radicals.

As amino acid higher alkyl ester salts, any of salts with mineral acids or organic acids is effective, but especially salts with a mineral acid such as hydrochloric acid, sulfuric acid or nitric acid, acetic acid, oxalic acid, formic acid, butyric acid, lactic acid, P-toluenesulfonic acid, acidic amino acid and pyroglutamic acid are preferable. Among these amino acid salts, C C

alkyl ester pyroglutamate of the amino acids selected' from the group consisting of glycine, alanine, valine, lysine, omithine and phenylalanine are most suitable, since they are easily soluble in water and exhibit excellent effect in controlling plant diseases.

The outstanding feature of the active ingredients of the fungicidal and bactericidal compositions of the present invention is that although they do not show so appreciable fungicidal or bactericidal activity against plant disease fungi or bacteria in in vitro test, they exert noticeable preventive effect when applied to plants in in vivo test and they have no phytotoxic effect on the plants and show rather plant growth promoting action.

The active ingredients of the present invention are especially useful in controlling the following suscepti' ble fungi (and bacteria) which attack food crops: Piricularia oryzae, the causative organism of rice blast; Xantomonas oryzae, the causature organism of rice leaf blight; citrus melanose; Colletotrichum lagenarium, the causative organism of cucumber anthracnose; Phytophthora parasitica, the causative organism of cucumber phytophthora rot; Sphaerotheca fuliginea, the causative organism of cucumber powdery mildew; Pseudoperonospore cubenis, the causative organism of the cucumber downy mildew; Cladosphorium fulvum, the causative organism of tomato leaf mold; Phytophthora fulvum, the causative organism of tomato late blight; Stemphylium lycopersici, the causative organism of tomato leaf spot and others.

The active ingredients of the fungicides and bactericides in the present invention may be directly applied to the susceptible plant surfaces or they may be applied thereto in any formulation such as granules, dusts, emulsifiable concentrates, wettable powders, pastes, oil agents, aerosols, fogs or fumigants with suitable solid carriers, liquid carriers, emulsifying and dispersing agents and so on, like the usual formulation well-known in the art. Examples of these carriers include clay, kaoline, bentonite, acidic terra alba, diatomaceous earth, calcium carbonate, nitrocellulose, starch, acacia, carbon dioxide gas, freon and the like. Also, there may be adequately compounded auxiliary agents, which are usually employed for formulation, e.g. surface active agents which serve as spreader, dispersing and emulsifying agents. Examples of such surface active agents are soap, higher alcohol sulfate, alkyl sulfonate, alkylaryl sulfonate, quaternary ammonium salt, polyalkylene oxide and the like. The preferred concentration of the active ingredient in the fungicidal composition is about 5 95% by weight for use as emulsifiable concentrates or wettable powders, while that is about 0.1 50% by weight for use as dusts or oil agents. However, these concentrations may be adequately varied depending on the purpose of use.

The amount of the fungicidal and bactericidal composition to be applied may vary according to such factors as the formulation of the composition, the type of the active ingredient, or the concentration of the active ingredient in the composition. Usually, it is about 30 g/l ares to 2000 g/l0 ares, preferably 50 g/il0 ares to 1000 g/l0 ares, as the active ingredient. If desired, greater amounts can be applied.

The active ingredients of this invention may also be employed in admixture with herbicides, insecticides, other fungicides, bactericides, soil conditioners and fertilizers such as urea, ammonium sulfate, ammonium phosphates, or potassium salts;

The following examples illustrate the production of various formulations for application of the fungicidal composition according to this invention. Parts are given therein as parts by weight.

EXAMPLE 1 Twenty parts of glycine laurylester 'DL- pyroglutamate, 2 parts of sodium lignin sulfonate, 4 parts of polyoxyethylene alkyl ether and '72 parts of clay were mixed together and milled to obtain E00 parts of wettable powder.

EXAMPLE 2 Two parts of L-phenylalanine 'myristyl ester-Di,- pyroglutamate and98 parts of talcum were mixed to obtain 100 parts of dust.

EXAMPLE 3 EXAMPLE 4 Ten parts of DL-valine laurylester hydrochloride, 15 parts of starch, '72 parts of bentonite and 3 parts of sodium lauryl alcohol sulfate were mixed together and milled to obtain 100 parts of granule.

The evaluation of the effectiveness of the fungicidal and bactericidal compositions of this invention against numerous plant disease fungi was accomplished by the following experimental examples.

Experimental example 1: inhibitory test against rice blast disease (in pot test) Rice stubbles (variety Jukkoku) were planted in synthetic resin pots of 6 cm in diameter, ten rice stubbles being planted per pot and were grown in the greenhouse. Various wettable powders prepared according to Example 1 were diluted with water to 500 ppm as the final concentration of test compound and each of the dilute aqueous solutions was appliedv to the rice plant seedlings of the four-leaf stage at a rate of 50 ml per pot using a spray-gun, and allowed to dry.

Spores of rice blast (Piricularia oryzae) which had been cultivated in a chaff culture medium containing yeast extract, soluble starch, saccharose and chaff were suspended in water, and sprayed inoculation on the rice plant seedlings uniformly. The rice plant seedlings treated thus were placed in an inoculation box at 28C and relative humidity of about 95 percent to be infected with Piricularia oryzae. Two days after infection, the number of disease lesions per leaf was counted and the preventive value was calculated according to the following equation:

Preventive value The results obtained were as shown 1n Table 1.

Table 1 Average number Preventive No. of test of disease Value compound lesions per leaf Phytotoxicity 1 15.2 54 2 12.9 61 3 8.6 74 4 l l .9 64 5 l3.5 59 6 7.6 77 7 10.9 67 8 13.5 59 9 9.9 70 10 13.0 61 ll 7.6 77 l2 l2.0 64 l3 8.6 74 14 13.5 59

Kitazin-P 6.9 79 Untreated plant 33.0 0

(Note) Test compounds No. l glycine laurylesterDL-pyroglutamate No. 2 DL-alanine laurylester hydrochloride No. 3 B-alanine laurylester hydrochloride No. 4 DL-valinc laurylester hydrochloride No. 5 L-phenyl alanine laurylester hydrochloride No. 6 N,N-dimcthyl laurylester hydrochloride No. 7 L-phenylalnnine myristylester-DL-pyroglutamate N0. 8 B-alanine cetylesterDL-pyroglutumate No. 9 L-lysine cetylesterDL-pyroglutamatc No. [0 DL-ulunine steruryl ester No. ll DL-glutamic acid-'y-lauryl ester No. 12 DL-alanine lauryl ester acetate No. 13 Z-aminoisobutyric acid lauryl ester'hydrochloride No. 14 DL-isoleucine myristyl ester'DL-pyroglutam'ate Control fungicide "Kitazin-P" (trade name, product of Kumiai Chemical Industrial Co., Ltd. emulsifiable I concentrate containing S-benzyl 0,0'-diisopropyl phosphorothiolate) was sprayed'at 500 ppm.: no phytotoxicity was recognized.

Experimental example 2: inhibitory test against rice leaf blight On the rice plant seedlings of the 4 leaf stage grown in the greenhouse similarly to Experimental example l, was sprayed each of the dilute aqueous solutions (concentration of test compound: 500 ppm) of various wettable powders prepared according to Example at a rate of 50 ml per pot and then allowed to dry.

Cells of bacterial leaf blight (Xantomonas oryzae) cultivated in a bacterial leaf blight culture medium at 27C for 3 days were suspended in water and inoculated with needle to the highest and second high leaves of the rice plant. In two to three weeks after inoculation, these leaves were infected with Xantomonas oryzae and the length of disease lesion per stalk was measured for the evaluation of effectiveness. The preventive value was calculated according to the following equation:

Preventive value The obtained results were as shown in Table 2.

Table 2 length of disease lesion Preventive No. of test per stalk value compound (mm) Phytotoxicity i 27.0 64 2 21.0 72 3 I28 83 4 7.5 90 5 32.3 57 6 i 30.0 60 7 24.0 I 68 .8 27.8 63 9 15.8 79 10 19.5 74 ll 24.0 68 l2 l6.5 78 l3 23.3 69 14 26.2 65

"Kumiai Phenazine l5.2 80 Mikasa Sunkel" 26.2 65

Untreated plant 75 '0 (Note) Nos. of test compounds used are the same with those of test'compounds in table I.

Kumiai Phenazine (trade name. product of Kumiai Chemical Industrial Co.. Ltd.. wettable powder containing phenazine 5- oxide) was sprayed at 62 ppm. "Mikasa Sunkel" (trade name. product of Mikasa Chemical lndustrial Co., Ltd.. wettable powder containing nickel dimethyldithiocarbamate) was sprayed at 1500 PPm.

Experimental example 3: inhibitory test against Citrus melanose I a. Test plant: shoots of about 3 years grown seedlings of citrus Onshu (two four trees planted in about 20 cm claypot) b. Solution used for test Each of various wettable powders prepared according to Example 1 was diluted with water to 500 ppm the final concentration of test compound and then sprayed uniformly on the test plants at a rate of 40 ml per two claypots.

As control fungicide, Daisen [trade name, product of Nihon-Nohyaku Co., Ltd., wettable powder containing zinc ethylene bis-(dithiocarbamate)] was sprayed at 1000 ppm.

c. lnoculum and the method of inoculation in order to prepare a suspension of pycnospores, distilled and sterilized water was poured on the culture twigs with citrus melanose in a test tube. The suspension containing about 200 of pycnospores was prepared under the observation of microscope of 150 magnifications and then sprayed inoculation on the test plants treated as above. After inoculation, the test plants were placed in the inoculation box at 27C and relative humidity of above percent for about 3 days. Then, they were transferred into the greenhouse.

d. The method of inspection About 2 3 weeks after inoculation, entire leaves of shoots were inspected for the development of disease and the state of infection was evaluated on a scale of 0 to 3 as follows:

0: no disease 1: one 50 of disease spots 2: 51 150 of disease spots 3: above 151 of disease spots The extent of infection and the preventive value were calculated according to the following equations (l) and (II), respectively.

(l) Extent ofinfection (1 X n 2 X n +3 n )/(3 X N) X 1100 wherein n n and n;; are number of leaves inspected to be the states of infection 1, 2 and 3, respectively and Nett @9 embers! e e (lI) Preventive value extent of infection of treated leaves extent of infection of untreated leaves (c) The results obtained were as shown in Table 3.

(Note) Nos. of test compounds used are the same with those of test compounds in table l.

Experimental example 4: inhibitory test against cucumber downy mildew Cucumber seeds (variety Shinhikari No. A) were planted in seed-beds at the beginning of Oct, three cucumber seeds being planted per seed-bed, and they were grown in a greenhouse made of vinyl resin. This experiment was performed as three-repeated cultivation.

Each of various wettable powders prepared according to Example l was diluted with water to 500 ppm as the final concentration of test compound and sprayed on the cucumber seedlings using a shouldering-sprayer four times in total on the 30th of Apr., the 6th, 12th and 19th of May so as to wet both sides of leaves thoroughly with the liquid dispersioneach time. The test plants treated thus were left to spontaneous infection. On the 23th of May, the state of infection was inspected with respect to both sides of ten leaves ranging from 11th to th leaf, and the preventive value was ee salate es9r lin:...! .r efa t w qu t m Preventive value number of leaves infected in treated plant number of leaves infected in untreated plant 4 4 67 8 64 6 4t 67 7 68 8 6 5O 8 64 9 5 58 6 73 l0 6 58 8 64 l4 3 75 7 68 "Daconil" 6 50 I2 45 Untreated plant 12 O 22 0 (Note) Nos. of test compounds used are the same with those of test compounds in table 1.

Daccinil" (trade name. product of Kumiai Chemical Industrial Co., Ltd., wettable powder containing tetrachloroisophthalonitrile) was sprayed at 1,250 ppm.

It will be understood from the results of inhibitory and phytotoxic tests that'the active ingredients of the present invention exhibit satisfactory effect in controlling numerous plant diseases and have no phytotoxicity.

What we claim is:

1. A method of combatting bacteria or fungi on plants which comprises applying to said plants a bactericidally 0r fungicidally effective amount of valine laurylester hydrochloride. 

